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DALLAS – March 3, 2010 – Like any successful team effort, the best qualities of two drugs commonly prescribed for enlarged prostate yielded better results than either of the medicines alone, according to a new study from UT Southwestern Medical Center.

The findings, published in a recent issue of the journal European Urology, compared treatments for three groups of study participants with enlarged prostates over four years. The study, which included more than 4,800 men, is one of the first to compare single and combo medication regimens in such a large group.

The first group of study participants received the drug dutasteride; the second group received tamsulosin; and the third received a combination of the two medicines.

“We found the combination therapy to be superior at reducing risk of BPH progression,” said Dr. Claus Roehrborn, chairman of urology at UT Southwestern and lead author of the study. “The two medications joined forces in terms of symptom control. On the strengths of both dutasteride and tamsulosin, participants reported fewer symptoms, and we observed a 25 percent reduction in prostate volume.”

Dr. Roehrborn added that subjects who received the combination therapy also showed a 50 percent reduction of prostate-specific antigen (PSA), a protein produced by both cancerous and noncancerous prostate tissue. PSA levels can be an indication of increased risk of cancer because cancer cells usually make more PSA than do benign cells, causing PSA levels in the blood to rise. Should PSA levels continue to rise after beginning therapy, patients should be monitored closely because the combination medicines do lower PSA readings, Dr. Roehrborn said.

Enlarged prostate, also called benign prostatic hyperplasia (BPH), is a common urologic condition that affects about 50 percent of men between the ages of 51 and 60 and up to 90 percent of men over the age of 80.

Symptoms of the condition can be prolonged and severe. Prostate enlargement creates pressure on the urethra, making it difficult to urinate, which can lead to acute urinary retention. This retention causes a host of other problems, including extreme discomfort and infections.

Researchers also looked at the data to determine if the number of study participants needing surgery for BPH decreased with the combination medication regimen. Compared with tamsulosin alone, the combination of drugs reduced the incidence of acute urinary retention by 67 percent and reduced the need for BPH-related surgery by 70 percent.

“We found a 65 percent decrease in the relative risk of acute urinary retention or BPH-related surgery compared with tamsulosin alone and just over a 19 percent reduction compared with dutasteride alone,” said Dr. Roehrborn.

Those taking the combination of drugs also were less likely than those in the other two groups to discontinue therapy, he said. Participants themselves noted that the combo medicines were most effective at reducing symptoms.

“There is currently no combination drug for doctors to prescribe for these patients,” Dr. Roehrborn said. “This research should provide physicians better information when they decide on a course of treatment for patients with BPH.”

Other researchers contributing to the study were from the Deaconess Clinic in Evansville, Ind.; State University of Rio de Janeiro; Universita Vita Salute San Raffaele, Italy; University of Toronto; and GlaxoSmithKline.

The study was funded by GlaxoSmithKline. Dr. Roehrborn is a consultant to the pharmaceutical company.